Excel - conditionally hide errors

I cannot figure out how to hide an error (or even why they're showing up in the first place). I have a formula starting in row 3 where I'm checking for matching values in a cell, then doing another formula based on the bool response. When I drag it down the column into the other rows, the next row looks good (shows blank) but every row after that shows an error. I tried using =IFERROR() and =ISERROR but cannot figure it out. The main formula in the cell is =IF(D3=D2, G2+E3,IF(D3="","",E3)) starting in row 3. How can I add something to the formula to hike the errors? Or if someone can explain why I'm getting them in the first place?